We joined all the red and white wires together.
A man will only slow down to match a woman's pace if they like her.
Hey, Steve. You’ve been living in Japan for a pretty long time now so don’t you think it’s time for you to adjust to Japanese customs? Stop being so picky and start eating fish.
You know that the alternative kanji meaning for 合 is join, which is what we're using here. The verb form of join is to join together, and it can also mean to unify and to match.
The reading comes from 合う, so if you know that reading you'll know this reading as well.